3D print farm vs injection molding
Your printers are full and a product is selling. Should you buy more printers or pay for a mold? It depends on what a printed part really costs you, including your time, and on how many you'll sell in the next year. Here's how to work it out, with real quotes.
The short answer
A print farm's cost per part is mostly your time: clearing plates, removing supports, checking and packing. Filament and printer wear are the smaller share. A mold's cost is mostly up front, and each molded part after that costs well under a dollar for a small part.
For a 41 g enclosure, a steel mold quoted at $8,063 paid for itself after about 4,000 parts once the farm's labor was counted. If your time is free, the same mold needs 16,000 or more. So the honest answer to "is it time to mold?" starts with what an hour of your time is worth.
What a printed part really costs your farm
Take one part from the kit we had quoted in October 2026: an enclosure 100 × 70 × 30 mm with 2 mm walls. Printed in PLA or PETG it weighs about 41 g and takes about 2.2 hours on a fast printer. Here's a typical cost per part for a small farm:
| Cost | Assumption | Per part |
|---|---|---|
| Filament | 43 g with purge and supports, at $20/kg | $0.86 |
| Printer wear | An $800 printer over 5,000 printing hours, plus nozzles, plates and belts: about $0.20 an hour | $0.44 |
| Electricity | About 120 W at $0.17 per kWh | $0.04 |
| Failed prints | 6% of plates reprinted | $0.08 |
| Your time | 4 minutes to clear the plate, clean up, inspect and bag, at $25 an hour | $1.67 |
| Total | With your time / without it | $3.09 / $1.42 |
Labor is more than half the cost, and it's the line most farms leave out. For comparison, a China print service quoted $4.03 each for ten of the same enclosure in PLA. That's their labor and margin on top of the same filament and machine time.
Change the numbers to match your farm: a slower printer adds machine time, a part that needs sanding adds minutes, and paying someone to run the farm turns "your time" into a wage.
What the mold side costs
The same enclosure, quoted by a China molder (ICOMold) and a US quick-turn molder (Protolabs) in October 2026. Prices are before shipping and import duty.
| Quote | Tool | Per part |
|---|---|---|
| Enclosure, China, steel tool, ABS | $8,063 | $0.93 at 1,000; $0.69 at 10,000 |
| Enclosure lid, China, steel tool | $4,665 | $0.70 at 1,000; $0.53 at 10,000 |
| Enclosure lid, US, aluminum tool | $3,395 | $2.77 at 500 |
| Small knob, US, aluminum tool | $1,895 | $2.46 at 500 |
Two things stand out. China steel tools cost more up front but make parts for well under a dollar. US aluminum tools cost less and arrive sooner, but their piece price at a few hundred parts is close to a farm's. Their case is capacity and a molded finish, not a lower price per part.
Parts from China also pay freight and import duty. Budget 20–40% on top of the piece price for small parts, and check today's duty rate for your product: it changes often.
The break-even
A mold pays for itself when the money saved on each part adds up to the tool:
Parts to break even = tool cost ÷ (your cost per printed part − landed cost per molded part)
For the enclosure, with the China steel tool and a third added for freight and duty, a molded part lands at about $1.24 at 1,000 and $0.92 at 10,000:
- Counting your time ($3.09 a print): each molded part saves $1.85–2.17, so $8,063 is paid back after 3,700–4,400 parts.
- Not counting it ($1.42 a print): each part saves $0.18–0.50, and the tool takes 16,000–45,000 parts to pay back.
Divide the break-even by what you sell in a month. Selling 300 a month, the mold pays back in a little over a year if your time counts. Selling 50 a month, keep printing.
Try it with your part
Set your part's size and drag the quantity. The printing line is what a print service typically charges, and the bottom of its shaded band is close to running your own printers, time included. The molding lines are estimates with the tool spread over the parts; switch the region to see US molders.
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When the farm runs out of hours
Cost isn't the only limit. A printer running 18 hours a day makes about 240 of these enclosures a month. Selling 1,000 a month takes four or five printers and about 70 hours of hands-on time, and every extra printer adds more plates to clear. A mold makes a part like this in under a minute, and the molder does the handling.
Signs it's time to look at a mold:
- You're buying printers to keep up with one product.
- Clearing and post-processing take more of your week than designing or selling.
- The same part has sold 200 or more a month for several months.
- Customers or a retailer want a consistent, smooth finish without layer lines.
- A wholesale order arrives that your farm can't print in time.
When printing is still the right call
- Many products, few of each. A mold is per part. Twenty products selling 30 a month each are a print farm's strength.
- Custom or personalized parts. Names, sizes or colors per order can't come out of one mold.
- The design is still changing. Editing a file is free; changing steel is not.
- Demand isn't proven. A mold is cash spent before the parts sell.
- The printed look is the product. Some customers buy layer lines and textures on purpose.
The usual answer: mold the best sellers
Most farms that move to molding don't stop printing. They mold the one to three parts that sell steadily, and keep the printers for new designs, variants, custom orders and the long tail. A few points make it work:
- Start with the part that has the highest monthly volume and the most printing time per part.
- An aluminum tool is a lower-risk first mold for a part whose demand you're still learning.
- Parts that ship together can sometimes share one mold (a family mold), which lowers the tooling for each.
- Keep printing the molded part until the first shots are approved, so sales don't stop while the tool is made.
Before you order a mold
- Material. PLA is rarely molded. Molders will suggest ABS, PC/ABS or PP, which behave differently: check stiffness, snap fits and heat.
- Design for molding. Add draft, even out wall thickness and remove undercuts where you can. A printable design isn't always moldable. What changes from printed to molded.
- Colors. Color is mixed into the plastic, and molders often set a minimum run per color.
- Minimum orders. Many molders want 500–1,000 parts per run. Plan stock and storage for it.
- Lead time. Allow several weeks for the tool and first samples, plus shipping, and more if the samples need changes.
- Cash. The tool and the first run are paid before the parts sell. What a mold costs, and why quotes vary.
Pilotrun prices every part of your product at any quantity, shows where each part should switch from printing to a mold, and writes the request to send molders so their quotes are comparable.